Italian patent applications No. 21003 A/80, No. 26205 A/80 and No. 26401 A/80, which are the priority documents for Massardo et al U.S. Pat. No. 4,388,323, issued June 14, 1983, describe, among other compounds, the compounds of formula I and the use thereof as acaricides: ##STR1## wherein R is an alkyl C.sub.8 -C.sub.11, R.sup.1 is a hydrogen atom, an alkyl C.sub.1 -C.sub.4, an alkenyl C.sub.2 -C.sub.4 or a group ##STR2## in which R.sup.2 is an alkyl C.sub.1 -C.sub.4, a cycloalkyl C.sub.3 -C.sub.6 or phenyl.
The compounds of formula I are endowed with a high acaricide activity which is exerted mainly against mite eggs.
It is known that a few copper compounds, such as copper sulphate, copper hydroxide, copper oxychloride, copper (I) chloride, copper protoxide and copper carbonate possess fungicidal properties and are widely employed also in admixture with one another for protecting plants from infections due to fungi.
It is furthermore disclosed in the literature that some copper salts, including copper oxychloride, exert a repellent action on Leptinotarsa decemlineata larvae and that they are employable, in admixture with insecticides, in the fight against such coleopter [Khim. Sel'sk. Khoz. 16 (11), 65 (1978); Chem. Abstr. 90:49599z].
As far as we know, however, a possible acaricide activity of copper compounds or of metallic copper has never been reported in the literature.
Moreover, tests carried out by use have confirmed that metallic copper and copper compounds do not possess any acaricide activity in particular against mite eggs.
Instead, we have surprisingly found that the coupling of copper compounds or of metallic copper with an acaricide compound of formula I synergizes the acaricide activity of the latter.
Thus, one object of the present invention is to provide synergistic mixtures endowed with acaricide activity, and consisting of a compound of formula I and of a copper compound or of metallic copper in a ratio by weight of from 1:1 to 1:250, referred to the metallic copper or to the copper content of the copper compound.
Metallic copper can be employed in the aforementioned mixtures in a finely divided form like that of electrolytic copper.
The copper compounds employable in the synergistic mixtures of this invention may be oxides, hydroxide, organic and inorganic salts of mono or divalent copper, also in admixture with one another. Useful compounds include:
copper (II) sulphate CuSO.sub.4 PA0 copper (I) chloride CuCl PA0 copper (II) chloride CuCl.sub.2 PA0 copper (II) carbonate CuCO.sub.3 PA0 copper protoxide Cu.sub.2 O PA0 copper (II) hydroxide Cu(OH).sub.2 PA0 copper oxychloride (a mixture of copper hydroxide and chloride) PA0 and mixtures thereof.
Since the acaricide action of the compunds of formula I is synergized when they are employed in the form of the mixtures of this invention, it follows that such mixtures offer also the considerable advantage of allowing reduction of the doses of compounds of formula I required while providing the same acaricide effectiveness.
The mixtures according to the present invention can be utilized in agriculture for protecting the plants against infestations due to acari.
The main acari of particular economic interest owing to the damages caused to the plants and owing to their very extensive diffusion in all cultivated areas belong prevailingly to family Tetranychidae, genera Tetranychus (T. urticae, T. telarius, T. pacificus, etc.), Panonychus (P. ulmi, P.citri, etc.), Bryobia (B. praetiosa) and Oligonychus.
Further species noxious to the cultures belong, for example, to family Eriophydae (genera Aceria, Eriophyes, Phyllocoptes, Phyllocoptruta, Vasates, etc.), Tarsonemidae genus Hemitarsonemus and Tenuipalpidae.
For practical use in agriculture, the mixtures of the present invention may be employed as such or in the form of agriculturally acceptable compositions or formulations.
Said compositions can contain, in addition to the synergistic mixture as active substance, solid or liquid inert vehicles as well as, optionally, other compatible additives, such as surfactants, suspending agents, emulsifiers, dispersants, adhesion promoting agents and the like.
According to the usual formulating practice, the compositions may be in the form of dry powders, wettable powders, pastes, concentrated emulsions, emulsifiable liquids, etc.
The synergistic mixture may be contained in said compositions in amounts ranging from 0.5 to 95% by weight depending on the type of composition and on the particular use for which it is intended.
The amount of acaricide mixture to be distributed in the area or on the vegetation to be protected depends on various factors such as the type of composition employed, the available application means, the degree and nature of the infestation, the type of culture to be protected, and the climatic and environmental conditions.
Generally, amounts of the synergistic acaricide mixture ranging from 0.1 to 2 kg/ha are sufficient for a very effective protection of the cultures from mite infestations.
If desirable, it is possible to prepare an extemporary mixture just prior to treatment.
Since many of the copper compounds employed are also endowed with a fungicide activity, it is logically expectable that mixtures of the invention exhibit also a fungicide activity.
The above-described formulations may be optionally additioned with other compatible active substances selected from among insecticides, acaricides, fungicides, phyto growth regulators, fertilizers, etc.
The compounds of formula I are furthermore endowed with an acaricide activity against hibernating eggs of acari. For this use, they can be employed as such or in compositions which contain, optionally, mineral oils. It is possible to employ the mixtures according to the present invention also for treatments against hibernating eggs of acari, optionally in compositions containing also such mineral oils.